Somatization disorder mediates the association of depression and anxiety with functional impairment in patients with heart failure

Previous studies have suggested that depression, anxiety, and somatization disorder are strongly associated with diminished functional status. However, research has not tested the mediational models of how depression and anxiety lead to functional impairment. The aim of this study was to examine whether somatization disorder mediates the association of depression and anxiety with functional impairment in heart failure (HF) patients. The self-reported questionnaires were applied to measure depression, anxiety, and somatization disorder. Functional status was evaluated by the NYHA Class. Ordinal logistic regression analysis was performed to examine the association of depression, anxiety, and somatization disorder with functional status. Mediation analysis was conducted to determine indirect effects. Functional impairment was both related to depression (OR = 2.257, 95% CI = 1.534-3.322, P < 0.001) and elevated somatization severity (OR = 1.042, 95% CI = 1.003-1.082, P = 0.032) in HF patients, whereas anxiety was not associated with functional impairment (OR = 0.659, 95% CI = 0.429-1.012, P > 0.05). Mediation analysis indicated that both depression and anxiety have indirect effects on functional impairment as mediated by somatization disorder in HF patients. Additionally, depression has direct effect on functional impairment of the patients.